The NIH studied three unidentified brains, one of which belonged to Seau, The Associated Press reported. The findings showed that Junior Seau had a disease similar to autopsies of people who suffered repeated head injuries.

The disease Junior Seau had has been found in other NFL players. Last month a center at Boston University studying CTE reported that 34 former pro players and nine who only played in college football were found to suffer from the disease.

One of the most famous cases was Dave Duerson, a former Chicago Bears defensive back who killed himself with a gunshot wound to the heart, attaching a note asking that his brain be studied. He was found to have CTE, and his family filed a wrongful death suit against the NFL claiming that the league didn’t do a good enough job preventing and treating concussions.

Junior Seau played 20 season in the NFL for the San Diego Chargers, Miami Dolphins, and New England Patriots. He died of a self-inflicted gunshot wound last year.

Seau’s family had donated his brain to the NIH to be studied, Yahoo! Sports reported. Last week Junior Seau’s widow, Gina, shared news of his disease.

“I was not surprised after learning a little about CTE that he had it,” added Junior Seau’s 23-year-old son, Tyler. “He did play so many years at that level. I was more just kind of angry I didn’t do something more and have the awareness to help him more, and now it is too late.

“I don’t think any of us were aware of the side effects that could be going on with head trauma until he passed away. We didn’t know his behavior was from head trauma.”

Tyler said Junior Seau’s disease would cause him to emotionally detach and “go away,” adding that the depression was getting worse.